Ferroli Aquasol with OpenTherm

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Ferroli Aquasol with OpenTherm

Postby BarthoD » Sun Apr 04, 2021 8:28 pm

Opentherm Gateway with Ferroli Aquasol Sun Boiler system - protocol and connetion issues.

Question: who has any info about the Ferroli Aquasol(4) and a connection to OTGW ?

I have an Ferroli Aquasol 4 with a sunpanel PV-size from HR-Solar. Avery good combination.
I want to read the status of the sunboiler system using the OTGW; using just a monitor function. I have no thermostat connected.

Ferroli documentation:
The system is capable of "speaking" OT (which seems to be standard at AgpoFerroli.
When connected to th AgpoTherm PLus is should be able to show OT 25 (Boiler water temp), 27 (Outside air temp) , 29 (Solar Storage Temp).

OTGW: I use the NODO OTGW with Wifi and I have updated all SW to 5.1 (the complete SW stack as advised by otgw.tclcode.com).
All OTGW commands seem to work but I get 0, nothing from the boiler.
I have added (AA command) the three messages 25,27,29.

When in Monitor mode nothing happens, in GW mode I see the 1-second request on my oscilloscope coming; but no response whatsoever from the boiler.
The power on the boiler output is 17,1V (=); the GW message is about 1,2V.
Test5 response on Voltage levels is Themostat (but not connected) 2.95 Boiler=0, Reference voltage 1.21. Test 6 : nothing, nada, no esponse.
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Re: Ferroli Aquasol with OpenTherm

Postby BarthoD » Fri Apr 09, 2021 8:39 pm

Today I learned that this boiler system is originally developed by ZEN (Zonne Energie Nederland - went broke 2014) and is taken over by Itho Daalderop. They are the builder of the equipment and electronics. On none of the sites of the companier there is any information, other van the mentioning of the boiler being able to provide a few temperaures and more via OpenTherm.

A comment that was made: the SUNboiler expects to be connected to an after heating (real) boiler with Opentherm. The path should be:
THERMOSTAT <opentherm> SUN Boiler <opentherm> BOILER (Naverwarmer)
The sugestion was made that the requests is coming from the T, picked up by the SUN boiler, who passes the message to the boiler, who returns an ACK + info, picked up again by the SUN boiler and passed back to the Thermostat.

In stead of the above, I have just connected the OTGW as a monitor to the SUNboiler. There is NO connected post-heating boiler (and there will not be).

My config is just:
(monitor) OTGW <opentherm> SunBoiler

The documentation suggestes that ANY after-heating boiler can do the job and can be connected with open-therm.
Question: what is the normal response from a boiler/heater back to a thermostat?

Because I use the OTGW just as a monitor I can use the 2nd connection to play the role as after boiler and send the right messages back (fake) ? What is the procedure and how can I close the loop?

The config will then be: :
OTWG T-connector <opentherm > sunboiler- B-channel
OTGW B-connecor <opentherm> sunboiler > T-channel


Any suggestions? Any experience?
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Re: Ferroli Aquasol with OpenTherm

Postby hvxl » Sat Apr 10, 2021 10:32 pm

It sounds like the SUN boiler is acting as a gateway. Probably it passes requests on to the post-heating boiler and fills in some of its own information. I can see how that is possible for MsgID 27, and 29. Most regular boilers will not provide this information. But MsgID 25 is normally reported by the boiler. If the SUN boiler changes that information, it could affect the ability of the thermostat to control the boiler.

I was going to suggest that you connect both interfaces of the OTGW to the two interfaces of the SUN boiler. But in that case you can't use the normal firmware on the OTGW. You would need to flash the interface firmware and create some external program to generate the opentherm messages. The program would send a request message to the OTGW. That sends it to the SUN boiler, which then sends some request to the OTGW. Upon receiving that request, the program creates a response, which then travels back along the path through the SUN boiler to the OTGW.By varying the requests, you can reverse-engineer what the SUN boiler does. But the first step is to see if the SUN boiler actually sends out a message on its B-channel when it receives something on its T-channel.
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Re: Ferroli Aquasol with OpenTherm

Postby BarthoD » Sun Apr 11, 2021 2:28 pm

I just linked the boiler OUTPUT frm SUN to the T-input of the OTGW.
Now I see messages as were they from a T..
T801A0000 Read-data Msg26 = 0
T10015A00 Write-data Ctrl Setpoint Msg01: 90
T00000300 Read-data Status msg=0 : 00000011 00000000

So I have a start .... I'm trying to get hold of an Agpo Thermostat to check all message; but this is already promising ... creating a loop .... now see what I can do with combining the channels.

I have one more option in my mind: connect the 2 chanlles from the boiler together at the B-side of the OTGW ..... I think this will work ??
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Re: Ferroli Aquasol with OpenTherm

Postby BarthoD » Wed Jun 02, 2021 9:16 am

I have tested with connecting an original Agpo OT thermostat.
I see the same messages passing. On the OUT of the SUN boiler it is still trying to connect to a post-boiler. I think the OT interface stops when it does not get the right responses. I have bought a CV PCB and connected, but no other results.

My question:
1- What is the exact flow of a normal OT transmission to a boiler (CV) and what should a gataway expect (message flow). Just an ACK ? But what are the details.
2- I tried the suggestion from Schelte from april 10th (as answered on april 11th)

It would be great if someone can create me a modified code with this "loop" of the OTGW. The only thing missing is a standard answer/command to simulate the boiler side NEXT tot the current OTGW, not in stead off, otherwise the OTGW function is useless.

Who can build this ? Who build this? Who can help / is able to program?
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Re: Ferroli Aquasol with OpenTherm

Postby hvxl » Fri Jun 04, 2021 1:55 pm

1. There are basically two types of OT requests that a thermostat sends: Read-Data and Write-Data. On a Read-Data request, the Data-Value is normally 0. The boiler responds to Read-Data requests with a Read-Ack, where it fills the Data-Value with the requested information. If the boiler doesn't support the message, it returns Unknown-DataId instead. On a Write-Data message, the Data-Value contains the related information. The boiler responds to these messages with a Write-Ack. It normally returns the same Data-Value it received. If the value is out of range, the boiler may return a corrected value (for example when the thermostat requests to set the water temperature higher than the maximum, the boiler may use the maximum and return that in the Write-Ack), or it returns Data-Invalid. Once again, if the boiler doesn't support the message, it returns Unknown-DataId. If you look through this forum you can find plenty of message logs you can use as a reference.

2. Based on your April 11 post, it looks like the SUN boiler is performing the role of a thermostat on the B-channel and boiler on the T-channel quite independently. Unfortunately you decided not to use OTmonitor for decoding the messages. So some important information is missing. I especially made OTmonitor to collect as much information as possible. It's a pity if people then don't use it when looking for support. In this case it would be useful to have timestamps of the messages to be able to tell how much time there is between them.

Once again, I would suggest to load the interface firmware in the OTGW. You have not confirmed you are using that. Then connect the two devices together as you proposed in your April 9 post. You'll have to (get someone to) write a small script that will respond to T reports as described in #1. The script should also periodically generate requests. A complication is that the OTGW can only handle one conversation at a time. When anything comes in on the thermostat interface, it will stop or ignore any other communication. The script needs to account for that.

I don't understand your remark "The only thing missing is a standard answer/command to simulate the boiler side NEXT tot the current OTGW, not in stead off, otherwise the OTGW function is useless." The current OTGW passes messages between the thermostat and the boiler. If you use the same hardware to simulate a boiler, there is nothing to pass the messages from the thermostat to.

If you mean that the OTGW should simulate both a thermostat and a boiler out of the box, then you're asking a bit much. Your situation is quite unique. To expect a device to magically do what you want is unrealistic.
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Re: Ferroli Aquasol with OpenTherm

Postby BarthoD » Tue Jun 08, 2021 4:38 pm

Hi Schelte,
I will try to start the tool on the output side of the sun boiler. I tried to get and connect a OT based boiler print, but this does not work (the print goes on error as there is nothing connected).

the sun boiler starts with a bout 1 second of messages to the boiler, when the boiler is not responding (and it does not, as there is none), the communication stops after about 2 seconds. These are the messages I posted in my previous post. I will try again to capture the messages after resetting/restarting the Sun boiler. Then I will post the report.
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